A new way of thinking about environmental problems has emerged since the 1980s. Environmental problems are increasingly seen as systematically entwined, with human action as their primary cause. We are in a new epoch in Earth’s history, the Anthropocene, and climate change is its most immediate and dramatic manifestation. The drivers of the Anthropocene can be seen through the lens of a simple equation: Environmental impact is the product of population, affluence, and technology. Nations and individuals vary greatly in their impacts, so questions of justice are unavoidable. Questions of justice extend across generations as well as among nations and individuals. Ultimately, we must ask what kind of world we want for ourselves and our children.